Various types of braking systems are known. For example, hydraulic, pneumatic and electromechanical braking systems have been developed for different applications.
An aircraft presents a unique set of operational and safety issues. As an example, uncommanded braking due to failure can be catastrophic to an aircraft during takeoff. On the other hand, it is similarly necessary to have virtually fail-proof braking available when needed (e.g., during landing).
If one or more engines fail on an aircraft, it is quite possible that there will be a complete or partial loss of electrical power. In the case of an electromechanical braking system, loss of electrical power, failure of one or more system components, etc. raises the question as to whether and how adequate braking may be maintained. It is critical, for example, that braking is available during an emergency landing even in the event of a system failure.
In order to address such issues, various levels of redundancy have been introduced into aircraft brake control architectures. In the case of electromechanical braking systems, redundant powers sources, brake system controllers, electromechanical actuator controllers, etc. have been utilized in order to provide satisfactory braking even in the event of a system failure. For example, U.S. Pat. Nos. 6,296,325 and 6,402,259 describe aircraft brake control architectures providing various levels of redundancy in an electromechanical braking system to ensure satisfactory braking despite a system failure.
Nevertheless, it is still desirable to continue to improve the level of braking available in electromechanical braking systems even in the event of a system failure. As an example, in the past, the level of antiskid control available during a system failure could be substantially reduced. Thus, it is desirable to have a brake control system architecture that provides improved antiskid control despite a power failure, system component failure, etc., as compared with conventional electromechanical braking systems.